Scalable video coding generally involves the generation of a video stream from which multiple versions of a same content item can be obtained, where the multiple versions differ according to one or more characteristics such as resolution, frame rate, signal-to-noise ratio (SNR), and/or bit depth. One approach to scalable video coding is embodied in the Annex G extension adopted in November 2007 for the H.264/MPEG-4 Part 10, Advanced Video Coding (AVC) standard jointly maintained by the Joint Video Team (JVT) partnership between the International Telecommunication Union Telecommunication Standardization Sector (ITU-T) Video Coding Experts Group (VCEG) and the International Organization for Standardization/International Electrotechnical Commission (ISO/IEC) JTC1 Moving Picture Experts Group (MPEG). A scalable video coding extension is also planned for the H.265/MPEG-H Part 2, High Efficiency Video Coding (HEVC) standard recently developed by the Joint Collaborative Team on Video Coding (JCT-VC) VCEG/MPEG partnership, which was formally published by the ISO/IEC on Nov. 25, 2013.
In a scalable video coding system, a multi-layered coding structure may be used that comprises a base layer and one or more enhancement layers. In the base layer, a base content version may be encoded. In each enhancement layer, a particular enhanced content version may be encoded that is enhanced with respect to one or more characteristics in comparison to the base content version. The encoding in any particular enhancement layer may be performed using predictions based on the base content version and/or using predictions based on one or more enhanced content versions associated with lower enhancement layers.
One technique that may be employed during encoding in any particular enhancement layer is inter-layer residual prediction. Inter-layer residual prediction may generally involve predicting residuals for blocks of a picture in an enhancement layer based on residuals for collocated blocks in a corresponding picture in the base layer or a lower enhancement layer. The use of inter-layer residual prediction may allow smaller, second-order residuals to be used in place of full residuals in generating an enhancement layer substream, and may thus enable a reduction in the bitrate associated with the enhancement layer substream. However, if a particular enhancement layer block has associated motion prediction characteristics that are inconsistent with those of the collocated lower-layer block, the residual for the collocated lower-layer block may not constitute a suitable basis for prediction of the residual for the enhancement layer, resulting in a large second-order residual and an incremental increase in the size of the enhancement layer substream.